A randomized, double blind, placebo controlled clinical trial of the preoperative use of ketamine for reducing inflammation and pain after thoracic surgery

Purpose We hypothesized that patients who received ketamine during thoracic surgery would benefit from suppression of the inflammatory cascade, represented by lower interleukin (IL)-6 and C-reactive protein (CRP) plasma levels. Methods This study was a randomized, double blind, placebo controlled clinical trial of ketamine in patients undergoing thoracic surgery. The setting was a single university teaching hospital. Forty patients who presented to the preoperative clinic prior to thoracic surgery (20 control, 20 treatment) were randomized to receive either a 0.5 mg/kg ketamine bolus or an equivalent volume of normal saline intravenously prior to chest wall incision. Plasma samples taken prior to induction of anesthesia and at 24 h following surgery were assayed for IL-6 and CRP levels. Verbal pain scores were reported at 4 and 24 h following surgery and at discharge. Results IL-6 plasma levels did not differ significantly at 24 h for patients receiving ketamine (245 ± 287 pg/ml, mean ± SD) compared to patients who received placebo (269 ± 210 pg/ml), p = 0.39. Additionally, CRP levels at 24 h were not significantly different (8.8 ± 4.5 mg/dl for ketamine, 9.3 ± 5.6 mg/dl for placebo patients), p = 0.37. Finally, verbal pain scores were not significantly different between patient groups at 4 or 24 h, or at discharge. Conclusions These findings suggest that the routine use of a single dose of ketamine prior to chest wall incision is not effective at reducing pain or inflammation in thoracic surgery patients at 24 h postoperatively.